Characterization of the peptide binding specificity of the HLA class I alleles B*38:01 and B*39:06.

B*38:01 and B*39:06 are present with phenotypic frequencies <2% in the general population, but are of interest as B*39:06 is the B allele most associated with type 1 diabetes susceptibility and 38:01 is most protective. A previous study derived putative main anchor motifs for both alleles based on peptide elution data. The present study has utilized panels of single amino acid substitution peptide libraries to derive detailed quantitative motifs accounting for both primary and secondary influences on peptide binding. From these analyses, both alleles were confirmed to utilize the canonical position 2/C-terminus main anchor spacing. B*38:01 preferentially bound peptides with the positively charged or polar residues H, R, and Q in position 2 and the large hydrophobic residues I, F, L, W, and M at the C-terminus. B*39:06 had a similar preference for R in position 2, but also well-tolerated M, Q, and K. A more dramatic contrast between the two alleles was noted at the C-terminus, where the specificity of B*39:06 was clearly for small residues, with A as most preferred, followed by G, V, S, T, and I. Detailed position-by-position and residue-by-residue coefficient values were generated from the panels to provide detailed quantitative B*38:01 and B*39:06 motifs. It is hoped that these detailed motifs will facilitate the identification of T cell epitopes recognized in the context of two class I alleles associated with dramatically different dispositions towards type 1 diabetes, offering potential avenues for the investigation of the role of CD8 T cells in this disease.

A case of 37 year long Behçet disease resembling Takayasu arteritis: An autopsy report.

A 19-year-old woman with a history of recurrent aphthous stomatitis and genital ulceration was diagnosed with Behçet disease. She was treated with steroids and immunosuppressive agents for more than 30 years, but multiple complications manifested including ileocecal ulcer, aortic valve regurgitation, renal failure, ischemic enterocolitis, and arteriosclerotic obliterans until her death at the age of 56 from pneumonia. An autopsy examination demonstrated an entirely calcified aorta and major aortic branches. The ascending aorta was dilatated 55 mm in diameter and branches were all stenosed. Microscopically, the aortic arch and its branches showed collagenous fibrosis of the outer media and adventitia, whereas coronary and abdominal aortic branches showed conventional atherosclerosis. Although the ante-mortem diagnosis was angio-Behçet disease, its pathophysiology along with her clinical history, morphology of the lead pipe-like aorta, predominant destruction of the outer arteries, and a human leukocyte antigen (HLA) haplotype of B39 were all suggestive of Takayasu arteritis. Thus, this case implies that HLA-B39 may be associated with the pathogenesis of arteritis like Takayasu arteritis, even if the primary disease is Behçet disease.